it’s not possible to create widget areas for posts but you can dragn’drop your widgets in the “Displayed Everywhere” widget area and use this plugin: http://wordpress.org/extend/plugins/widget-logic/ to display the widget on certain pages/posts only.

It’s not possible to add different sidebars – I’m sorry. You can use widget logic to display widgets on certain pages/posts only (use the code above but instead of “198” fill in the post/page id of your choice).